Effect of Dental Finishing Instruments on the Surface Roughness of Composite Resins as Elucidated by Atomic Force Microscopy

Abstract

Roughness increases significantly after finishing procedures. The aim of this study was to assess by the atomic force microscope~AFM! the effect of finishing instruments on the surface roughness of composite resins. A nanofiller composite resin~Filtek Supreme, 3M-F! and a microhybrid composite resin~Point 4, Kerr-P! were selected. The finishing procedures were done with a 30-blade carbide bur~C! and a 30-mm finishing diamond bur~D!. Standardized specimens were produced and divided into six experimental groups n ϭ 4! according to~1! composite resin,~2! absence of finishing~Mylar matrix-M!, and~3! finishing instrument~FM, PM, FC, FD, PC, PD!. The mean surface roughness was evaluated by AFM in the contact mode. FM and PM groups were assessed statistically by the Student's T test, and FC, FD, PC, PD groups were submitted to variance analysis~ANOVA!, both at 5% significance. The mean surface roughness values, in nanometers, were FM, 23.63~b!; FC, 283.88~c!; FD, 510.55~d!; PM, 12.52~a!; PC, 343.98~c!; PD, 531.64~d!. Microhybrid composite displayed less roughness than nanofiller composite in the absence of finishing procedures. The 30-blade carbide bur produced less roughness compared to the extra fine diamond bur.

Surface roughness and morphology of resin composites polished with two-step polishing systems

“…Pre-roughening with diamond burs results in a non-homogeneous surface texture 22) and creates different surface roughnesses on different materials 22,27) . Therefore, in this study, pre-roughening was standardized using a polishing machine with 320-grit SIC paper that generated roughness similar to that created with a 30/40-µm diamond bur, which represents clinical contouring and finishing 22) .…”

Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

“…For the finishing and polishing procedures, the specimens were positioned in a bipartite stainless steel matrix with central height adjustment 26 , which prevented the contact of the finishing and polishing instruments with the surface of the matrix, hence facilitating implementation.…”

“…In spite of much effort in standardizing the methodology in this study, it is possible that the surface of the specimens prepared with the polyester matrix was not free of imperfections due to the nature of the resinous matrix 9 and the possible irregularities in the polyester matrix 9,22,26 . This fact may have resulted in greater surface roughness for the groups without finishing and polishing.…”

Effect of finishing and polishing on color stability of a nanofilled resin immersed in different media

“…Th e specimens were made using a two-piece stainless steel matrix with four circular holes measuring 10 mm in diameter and 2 mm thick 24 . Th e composite resin was inserted into the matrix in a single increment, over which a polyester strip (K-Dent -Quimidrol, Joinville, SC, Brazil) and a glass plate were placed.…”